Froth flotation method



2,990,958 FROTH FLOTATION WTHOD Ernest W. Greene, Westfield, and JamesB. Duke and Joseph L. Hunter, Metuchen, N.J., are to Minerals &Chemicals Philipp Corporation, a corporation of Maryland No Drawing.Substituted for abandoned application Ser. No. 779,066, Dec. 9, 1958.This application Dec. 9, 1958, Ser. No. 779,061

27 Claims. (Cl. 209-166) The subject invention relates to an improvedmethod for concentrating very finely divided (or slimed") minerals andores into components by froth flotation and relates, more particularly,to an improved method for conditioning minerals and ores of suchcharacter for froth flotation for the purpose of enhancing the degree ofconcentration thereof.

Froth flotation is a widely practiced process for separatingmulticomponent minerals and ores into components. The process isamenable to a large variety of minerals and ores and provides in manyinstances, a highly economical and efficacious method for concentratingcomponents of minerals and ores.

There are, however, several limitations to the froth flotation process.One of the most serious drawbacks to the process is that very finelysized feed, viz., feed comprising particles passable through a 200 meshscreen, and particularly those of -l microns or finer, are notetiectively concentrated by froth flotation. Such very fine particles orslimes may be naturally occurring constituents of a mineral or ore ormay be artificially produced during the grinding of the mineral or oreto a suitable size for mineral liberation. It is well-known to thoseskilled in the art that certain materials will not fioat in a frothflotation process when ground to an exceedingiy fine size, although theywill float under the same conditions when provided in coarser grainsize.

At any rate, those who have heretofore attempted to concentratecomponents of vanious slimed minerals and ores by froth flotation havemet with little success and have, accordingly, advocated desliming priorto flotation, when possible, although such practice adds to theprocessing costs and loss of valuable mineral. Further, it is generalpractice to desist, when possible, from grinding certain ores andminerals to a degree at which slimes are artificially produced.

In many instances slimes cannot be avoided and removed, when present,for economic or practical reasons. For example, kaolin clay is anaturally slimed mineral, consisting predominantly of particles 2microns or finer, the clay being mechanically associated with veryfinely divided color body impurities which detract from the value andutility of the clay in many applications. Prior art efforts tobeneficiate the clay by floating the color body impurities have met withmediocre success at best unless the clay tcedwas prefractionated toreduce the quantity of fines. Certain relatively coarse grained minerals and ores, too, have defied efiective froth flotation since theyare not readily reduced to suitable flotation feed size withoutprovision of fines when they are ground to overcome interlocking betweendissimilar mineral genera to permit their flotation. As examples of oreswhich become slimed when ground for flotation feed may be citedmagnesite-brucite ores and uraninite ores (from which concentration ofuranium values are desired). Other examples are well-known to thoseskilled in the art. The technical literature is replete with reports ofpoor results in beneficiating such slimed minerals and ores by frothflotation with prefractionation or desliming.

Accordingly, a principal object of the subject invention is theprovision of an improved froth flotation tech sass Patented July d, 3961nique wherein very finely divided or slimed minerals and ores are usefulas feed material.

Another object of the invention is the provision of a froth flotationprocess whereby slimed minerals and ores may, without slime removal, bemore efiectively concentrated than by employment of prior art methods.

A more specific object of the present invention is the provision of animproved means for conditioning slimed minerals and ores for frothflotation in order to realize a higher degree of collection of the oiledconstituent or constituents of said minerals and ores.

These, and further objects and advantages, are realized in accordancewith the instant invention wherein the conditioning of slimed mineralsand ores for froth flotation is accomplished with two essential agentswhich, cooperatively, permit improved beneficiation of very finelydivided feed.

Broadly stated, our invention contemplates a process for the frothflotation of very finely divided rnulticomponent mineral masses in whichthe finely divided or slimed feed is conditioned with (l) a reagentcapable of selectively oiling a desired component of the feed for entryinto the froth during the concentration step, and (2) a. particulateauxiliary mineral which is collector coated (oiled) in a manner suchthat it is also capable of entry into the froth during the concentrationstep, thereby enhancing or promoting the flotation of the se lectivelyoiled fraction of the feed. The feed thus conditioned and in the form ofan aqueous pulp is subjected to froth flotation thereby to produce afroth product which is a concentrate of the oiled water-repellentcomponent of the feed in intimate association with the collector-coatedwater-repellent auxiliary mineral particles and a machine dischargeproduct which is a concentrateof the component of the feed which has notbeen selectively oiled and is thus water-wettable.

Obviously, there must be an explanation why the use of oiled auxiliarysolid particles improves the flotation of very finely divided componentsof a feed material, especially in. view of many cases where, indeed, noseparation at all is obtained with ordinary froth flotation procedures.The results we have obtained indicate that a probable explanation wouldbe a marked afiinity between oiled auxiliary mineral particles and theoiled component of the feed. On this basis, it appears likely that theoiled auxiliary particles form a nucleus for the attachment of thefinely divided oiled fraction of the feed. These loaded carrierparticles are obviously particularly amenable to froth flotation andseparation from the water-wettablc residual fraction of the feed. inother words, the loaded carrier particles are adapted to airbubbleattachment.

Thus, the method of our invention comprises a novel concept in theflotation art that definitely extends its application to slimed mineralsin the -l0, 5 and micron particle size ranges.

An interesting and surprising feature of our invention is that theauxiliary mineral we employ may contain significant quantities ofparticles 10 microns or finer. It has been previously brought out thatconventional froth flotation procedures are not adapted to the eificientflotation of such fine particles.

The present invention, in its broadest aspect, is not limited tobcneficiation of any species or genus of finely divided minerals or oressince its benefits are realized when employing a variety of minerals andores in which the slime is of natural or artificial origin. Our methodmay be applied with equally good results to feed in which a valuedcomponent is concentrated in the froth product or machine dischargeproduct or in which both froth and machine discharge products are valuedmaterials.

The very finely divided or slimed minerals and ores to which ourinvention relates are those which consist essentially of particles finerthan about 200 mesh and is applicable to feed of 10 microns, 5 or -2microns.

Any finely divided mineral or ore may be beneficially conditioned forfroth flotation in accordance with the present invention provided: (1)the components thereof which it is desired to separate are liberatedfrom each other, and (2) one of said components must differ from theother to the extent that it contains a substantial amount of a componentwhich is capable of being selectively coated with an orientedhydrophobic coating, the coating being held on the surface of particlesof the component by chemical or physical forces or combinations thereof.

The method of our invention is subject to numerous variations, e.g., byappropriate choice of auxiliary minera], the feed may be reagcntizedwith the same reagents as used in reagentizing the particulate auxiliarymineral to render said mineral suitable as a conditioning material, andthe reagentization of feed and auxiliary mineral in such a case may beperformed concurrently or separately, this depending on the relativeafiinities for the reagents of the solids being treated. However, whenthe choice of auxiliary minerals is such that it cannot be collectorcoated by the reagent or reagents used to collect the desired componentof the feed, then the reagentization of auxiliary mineral will be doneindependently of the reagentization of the feed.

In accordance with an embodiment of our invention, the froth product isseparated into an auxiliary mineral component and a component of thefeed which has been floated. In this case the recovered auxiliaryparticles may be reused in a subsequent conditioning treatment afterreoiling when necessary.

In accordance with still another embodiment of our invention, the frothproduct or machine discharge product is reconcentrated.

Pursuant to still another embodiment of our invention, the compositefroth product of a concentration step is used in one or a plurality ofsubsequent concentration steps as the particulate auxiliary mineral,after treating the composite froth product with additional quantities ofreagents when necessary.

By application of our conditioning treatment, slimed ores and mineralsmay be more effectively concentrated than by prior art. techniques and,in some instances, slimed ores and minerals, never heretoforeconcentratable by froth flotation, may now be bcneficiated with a gooddegree of efficiency.

More specifically, in accordance with the method of the instantinvention, we initially select as a feed material a very finely dividedmulticomponent mineral or ore, viz., one which contains a prcponderatingamount of 200 mesh particles, and which is inherently capable ofbeneficiation by froth flotation by virtue of liberation of com.-poncnts which are to be separated and ability of one of the mechanicallyseparable components to be selectively collector coated with an orientedwater-repellent coating. The feed may have been subjected to previoustreatment such as, for example, flotation, tabling, hydraulicclassification, grinding, chemical treatment, etc.

The novel method of our invention can be applied to both metallic andnonmetallic ores and minerals and should be particularly beneficial inthose cases in which difliculty is experienced in the flotation step dueto the presence of slimed mineral particles.

As a specific example of suitable feed for our flotation method may hecited kaolin clay which is discolored by titaniferous and, in someinstances, ferruginous impurities. Kaolin clay in the form of adispersed aqueous slip may be reagentized, in accordance with ourinvention, with a negative-ion collector such as oleic acid or tall oilin an alkaline pulp, in conjunction with a collector-coated particulateauxiliary mineral, for flotation of the colored impurities in the clay.Another suitable feed material is uraninite ore which becomesartificially slimed when ground to liberate the uranium values; theslimed uraninite feed may likewise be reagentized with a negative-ioncollector such as oleic acid, in an alkaline pulp, in conjunction with acollector-coated particulate auxiliary mineral such as calcite, forflotation of the uranium value in the ore.

As has been brought out hereinabove, reagentization of feed andauxiliary mineral particles to condition the feed for concentration byfroth flotation may be carried out simultaneously or separately,depending on the nature of the feed and the auxiliary mineral.

We may reagentize the feed, auxiliary mineral or mixtures thereof in anysuitable apparatus ordinarily used for reagentizing ores and minerals,such apparatus being well-known to those skilled in the art and beingfully described in the literature. Ordinarily, the reagents will beadded to the particulate solid when the solid is dispersed in anyaqueous medium, utilizing a dispersant when necessary to overcome thetendency of the solid particles to flocculate. However, it is fullywithin the compass of our invention to reagentize the feed, auxiliarymineral or mixtures thereof simultaneously with the step of grinding thesolids to a suitable grain size for the flotation process.

In those instances where the auxiliary mineral is of a character suchthat it may be reagentized with the same reagents utilized for treatingthe ore or mineral feed, the process is simple and requires merely theincorporation and intimate admixture of the auxiliary mineral with thefeed material during the reagentizing step. The reagents employed mustbe calculated to provide not only for floating a fraction of the feedbut also for floating the auxiliary mineral. In some instances, evenwhen the reagents are the same for feed and auxiliary mineral, it willbe desirable to reagentize feed and auxiliary mineral separately,preferably each in the form of a dispersed aqueous pulp, and then admixthe reagentized materials; an instance where such practice is indicatedis when the auxiliary mineral or feed has surface characteristics suchas to preclude proper reagentizing of the other material.

In some instances, separate reagentization of feed and carrier isobviously mandatory. In such a case. the preferred practice will be toprepare an aqueous pulp of dispersed feed rcagentized with appropriatereagents, separately reagcntize an aqueous pulp of the auxiliarymineral, admix the pulps and subject the admixed pulps to frothflotation.

The particle size of the particulate auxiliary material may vary withina wide range, which, of course, must lie within the range of materialfioatable in the presence of the reagentized feed, i.e., usually withinthe range of from about 14 mesh (Tyler standard) to 5 microns or finer.It has been our experience, however, that generally speaking particlessomewhat finer than 325 mesh may be preferred to particles coarser than325 mesh.

As an auxiliary mineral, we may employ any mineral of suitable sizewhich is capable of being provided with an oriented hydrophobic surfacecoating, the coating being of a character such that the auxiliarymineral will be fioatable in the presence of the particular rcagentizedfeed pulp which is being beneficiated. Thus, the choice auxiliarymineral will depend, inter alia, on the pH employed in the flotationcell and the ionic nature of the collector reagent.

As examples of suitable particulate auxiliary minerals may be mentionedcalcite, barytes, kyanite, silica sand, anatase and fluorspar. Auxiliaryminerals may be unior multicomponent materials or may be mineraladmixtures. Suitable reagents for floating the auxiliary mineralsabove-specified are described in Taggart Handbook of Mineral Dressing12, 116-128 (1950 edition) or may be experimentally determined. However,it will be readily apparent to those skiiled in the froth flotation artthat accuses any mineral which may be appropriately conditioned forflotation in the presence of the reageutized feed pulp is Within thecompass of our invention. The particular choice of reagents for theauxiliary mineral particles should be based on'the nature of the solidsin the feed The optimum proportion of auxiliary mineral relative to feedsolids may also vary within wide range, the minimum amount of auxiliarymineral weight basis, ordinarily being at least equal to and frequentlyexceeding the weight of the fraction of the feed which is to be floated.Moreover, the amount of auxiliary mineral may be substantial relative tothe floated feed and may be equal or double or more the weight of thetotal feed. We have, for example, achieved a substantially equivalentdegree of concentration of color body impurities from a gray sedimentarykaolin clay utilizing reagentized calcite as the carrier for said colorbody impurities, when calcite was used in amounts from 5 to 200% byweight of the clay feed.

In the reagentization of feed and auxiliary minerals, there may be usedin addition to the hydrocarbon-containing collector, promoters,inhibitors and/or other appropriate flotation adjuvants. pH adjustorsmay be employed when their use is indicated.

Preferably, subsequent to the reagentization of the feed and theauxiliary mineral particles, the pulp is subjected to aeration (andusually mechanical agitation) in any suitable flotation cell. Additionalreagents may be added during this step if required. As a result of theaeration, the colored impurities, collector coated, are carried upwardinto the froth in association with the reagentized particles ofauxiliary mineral and the composited froth is separated from thetailings or machine discharge product.

The concentration may be accomplished in any suitable apparatus for thepurpose, such apparatus being wellknown in the art and forming no partof the subject invention. Appropriate frothers may be added when theiruse is indicated.

As in other flotation processes, product recovery and efficiency ofconcentration maybe improved by retloating either the froth or machinedischarge products through the flotation cell.

When desired, the auxiliary mineral may be separated from the floatedfraction of feed by any appropriate method. The choice of method willdepend on many factors which include, inter alia, the relative grainsize and specific gravity of the auxiliary mineral and the floatedfraction of feed, and the physical and chemical surface characteristicsof the solids.

in other situations it may be advantageous to employ an auxiliarymineral which is a desirable component when admixed with the floatedfeed material.

The method of our invention as applied to the beneficiation of kaolinclay discolored with titanifcrous and ferruginous matter will be morefully illustrated in the following examples. it will be understood thatthese examples are given only for illustrative purposes and that ourinvention is not limited to the specific materials and quantities setforth therein since other finely divided minerals and ores may be usedin lieu of kaolin clay with equally good results by judicious selectionof reagents and operating conditions.

CRUDE KAOLIN SLIP PREPARATION Twenty-five pounds (dry basis) of crudeGeorgia kaolin known as Klondyke Crude was stirred with about 100 poundsof water (Culligan softened) until practically all of the clay lumpswere disintegrated. The slurry was screened to remove all plus 325 meshgrit. The degritted clay had a particle size distribution such that 98%by weight of the particles was l5 microns, 92% was microns, 80% was -5microns, 50% was --1.5

microns and 15% was -0.5 micron (all particle sizes referring toequivalent spherical diameters).

Example I 292.5 grams (500 grams dry) of the -325 mesh crude kaolin slip(above-described) was pulped with more water into a 1000 gram laboratoryMinerals Separation Airflow flotation machine to a concentration ofabout 10% solids.

The kaolin pulp was agitated without air for 1 minute with 0.3% (basedon dry weight of clay) sodium silicate. While the machine was running,the following reagents were added to the pulp: ammonium sulfate, 5.0pounds; ammonium hydroxide, 5.0 pounds; crude tall oil fatty acid, 5.0pounds; neutral Calcium Petronate, 5.0 pounds; and American CyanarnidReagent 301, 2.5 pounds. The neutral Calcium Petronate was supplied bySonneborn Chemical Company and has the following analysis:

Percent Calcium sulfonate complex 41.0 Sodium sulfonate Trace Mineraloil 58.5

Water 0.5 M

Percent Ca in sulfonate complex 2.86

American Cyanamid Reagent 801 is a water-soluble petroleum sulfonateproduced by American Cyanamid Company under their designation 801." Thequantity of reagents are pounds per ton of dry kaolin. The pulp wasconditioned with the above reagents for 10 minutes with the air off andthen air was admitted to the flotation machine and a froth removed for10 minutes.

To the pulp remaining in the flotation machine the following rcagentswere added: ammonium hydroxide, 1.5 pounds; crude tall oil fatty acid,1.2 pounds; neutral Calcium Petronate, 1.2 pounds; and American CyanamidReagent 801, 0.6 pounds. The reagent quantities are pounds per ton ofdry clay. The pulp was further conditioned for 10 minutes without airand then subjected to froth flotation, removing a second froth productfor 10 minutes. The two froth products were combined. The results ofthis experiment are given below, wherein brightness index refers to abrightness value obtained by TAPPI standard method T-646 [11-54, asdescribed on pages 159A and 160A of the October 1954 issue of TAPPI (amonthly publication of the Technical Association of the Pulp and PaperIndustry). The method measures the light reflectance of a clay sampleand thus gives a quantitative indication of its brightness or whiteness.

Percent Percent Brlght- Percent Weight uess Tl0 Index Flotation FrothProducts 18,8 1 69.1 X 5. 37 Flotation Machine Discharge Products. 81.281.0 0.95 325 Mesh Crude Kaolin Feed 100.0 78.8 1.78

1 Calculated values.

Following are examples of flotation of colored impurities from kaolinclay using auxiliary minerals whereby the ll'gPOlifil'ii. advantages ofthe present invention are rea zed.

Example II agitated (air off) with 0.3% (based on dry weight of clay)sodium silicate for 1 minute. While the machine was operating thefollowing reagents were added to the pulp: ammonium sulfate, 5.0 pounds;ammonium hydroxide, 7.5 pounds; crude tall oil fatty acid, 6.2 pounds;neutral Calcium Petronate, 6.2 pounds; and American Cyanamid Reagent801, 3.1 pounds. Reagent quantities were pounds per ton of dry kaolin.After the reagents were added the pulp was conditioned for 5 minutes.

400 grams of 325 mesh natural calcite (Thompson Weinman 8: Company No. 1white) was pulped with water to 68% solids and conditioned for 5 minutesin a paddle type agitator with the following reagents: caustic soda,0.25 pound; and crude tall oil fatty acid, 4.0 pounds. Reagentquantities were all pounds per ton of calcite. The calcite was 98% byweight -40 microns, 36% 10 microns and 10% 3 microns.

The reagentized calcite was added to the reagentined kaolin pulp in theFagergren flotation machine and the whole conditioned together for anadditional 2 minutes without aeration.

The reagentized kaolin-calcite pulp was transferred to a 1000 gramMinerals Separation Airflow flotation machine and diluted with water toabout 13% total solids. The diluted reagentized pulp was subjected tofroth flotation removing a froth product for 5 minutes and the flotationmachine discharged. The first froth product was repulped into theflotation machine and refloated for 5 minutes without additionalreagents. The froth product was refloated to more times. The followingmetallurgical results were obtained.

Percent Per- Per- Brlzht- Per- Per- Percent Products cent ness cent centcent. T101 Wt. Index T10: CaCO; F0101 Distritiution Feed 100.0 70 8 1.780.40 100.0 Mach. Dlsch. 1 52. 5 84.9 0. 40 0.2 0. 27 11.8 010011. Dlsch.2--. 25. 5 84. 5 0. 44 1.5 0. 28 0.2 Mach. Dlsch. 3 12.0 84.0 0. 48 3.10.28 3. 4 Which. Disch. 4. 5.5 84 0.54 3.8 0.?0 1.6 Froth Prod. l 4.530. 44 3.11 77.0 Total Mach.

Dlseh. 95 84.0 0.43 1.1 0 27 23.0

No'rE.-l\1etallurg1cal balance ba ed on dry kaolin feed.

the kaolin clay substantially, both with respect to the yield ofbeneficiated product, brightness index and titania reduction. It will benoted that the brightness of the bcneflciated product was 81.0% inExample 1 whereas by the method of our invention the brightness wasincreased to 84.6% with an excellent weight recovery of 95.5%.

Example III This example illustrates the embodiment of the instantinvention wherein the feed and the auxiliary mineral particles arereagentized simultaneously in the form of an admixed aqueous pulp.

985 grams (200 dry) of -325 mesh crude kaolin slip (same as Example I)was pulped with water into a Fagergren flotation machine to solids. Thekaolin pulp was agitated with 0.3% (based on dry weight of clay) sodiumsilicate for 1 minute. 400 grams of 325 mesh natural calcite was addedto the agitated kaolin pulp and the whole diluted with water to aboutsolids. While the machine was operating the following reagents wereadded to the pulp: ammonium sulfate, 5.0 pounds; am-

monium hydroxide, 6.3 pounds; crude tall oil fatty acid,

' 14.2 pounds; neutral Calcium Petronate, 6.2 pounds; and

Per- Percent Per- Per- Percent Products cent Brightcent cent 10; Wt.ness Ti 0; C800; Distri- Index button 78. 8 1. 78 100. O 85. 4 0. 30 2.9 6. 7 S5. 5 0. 3t 3. 8 5. 1 85. 0 0. 30 3. 0 3. 4 85. 1 0. 40 5. 9 2. 23. 8 18. 37 82. 6 85. 3 0. 34 3. 6 17. 4

Norn..\1etallurg1 xa1 balance based on kaolin teed.

Example IV This example was principally the same as Example II exceptthe kaolin slip was composed of another type of kaolin from a differentarea and is commonly called Georgia Gray Kaolin." The clay ischaracterized by a very low brightness index. Reagents and operatingconditions were those detailed in Example 11. The metallurgical resultsare shown below.

from a different area and which has a higher brightness index level thanthe kaolin used in Example 11. Reagents and operating conditions werethose detailed in Example II. The results obtained are shown below.

Per- IllCPDt Per- Per- I'ur- Percent Products cent Bright, cent centcent '1101 Wt. rims T10; (NICO, F120; Distrl Index button Food 100.0$1.9 1.05 0.30 100.0 Mach. DIsciL 87. 5 P 0. 0 (l. 42 0 9 0. 29 19. 0Froth Prod..." 12.5 48.8 1.3.01 0.88 81.0

Example VI This example illustrates the benefication of a fine fractionof discolored kaolin clay by froth flotation utilizing a reagentizedcalcite carrier in the conditioning step.

The clay feed in this experiment was a fractionated Georgia kaolinhaving a particle size distribution such that about by weight of theparticles had an equivalent spherical diameter of 3 microns or finer andabout 50% by weight was 0.5 micron or finer.

985 grams of a slip of the clay containing 200 grams of clay were pulpedwith water into a laboratory Fagergren flotation machine to aconcentration of 10% solids. While the pulp was agitated (air off), thefollowing reagents were added to the pulp: ammonium sulfate, 5.0 pounds;ammonium hydroxide, 5.0 pounds; crude tall oil fatty acid, 6.2 pounds;neutral Calcium Petronate, 6.2 pounds; and American Cyanamid Reagent801, 3.1

pounds. Reagent quantities were pounds per ton of dry I microns, and 10%was 3 microns, was pulped with water to 68% solids level and conditionedfor 2 minutes in a paddle type agitator with the following reagents:caustic soda, 0.25 pound; and crude tall oil fatty acid, 4.0 pounds (allreagent quantities being in pounds per ton of dry calcite).

The reagentized calcite was added to the reagentized kaolin pulp in theFagergren flotation machine and the whole conditioned together for anadditional 20 minutes. The solids content of the composited pulp was21%.

The reagentized kaolin-calcite pulp was transferred to a 1000 gramMinerals'Separation Airflow flotation machine and diluted with water toabout 17% total solids. The diluted reagentized pulp was subjected tofroth flotation removing a froth product for 5 minutes. The flotationmachine was discharged and the first froth product was repulped into theflotation machine and refioated without additional reagents for minutes.The froth product was refioated two more times and the machine dischargeproducts of all steps were composited.

The results of this experiment are summarized below.

Percent Percent Weight Brightness Index Prelrnctionnted Kaolin Feed100.0 80.9 Flotation Froth Products 5. 5 Flotation Machine DischargeProducts 94. 5 M2 This example is similar to Example Ill except thatmaterially less calcite was used in conditioning the clay.

425 grams (dry basis) of the -325 mesh Klondylte kaolin slip was pulpedwith water into a Fagergren fiotation machine to 10% solids and 30% ofThompson Weiman Company No. 1 white calcite (based on the dry clayweight) added to the pulp. The pulp was conditioned for 17 minutes (airofi) with the following reagents: ammonium sulfate, 5 pounds; ammoniumhydroxide, 5 pounds; tall oil, 7.6 pounds; and 6.2 pounds of Calciumletronate (all reagents expressed in pounds per ton of dry clay). The pHof the reagentized pulp was 9.2. The reagentized pulp was transferred tothe Minerals Separation Airflow machine and subjected to a single floatfor 10 minutes. The percent recovery was 50.1%, based on the dry clayweight. The feed clay had a. brightness of 78.8% and the beneficiatedproduct had a brightness of 87.2% (which was increased to 89.6% bybleaching). The titania analysis of feed clay was L78 and beneficiatedproduct was 0.37. The Fe O analysis of feed was 0.33.

We have obtained beneficiation of kaolin using other carriers withsimilar and different collector reagents. As examples of such carriermaterials may be cited calcium fluoride, ground marble and ground silicasand, utilizing as the collector reagent therefor tall oil in the caseof marble and calcium fluoride and octadecylamine acetate in the case ofthe silica sand.

We claim:

1. The method for beneficiating a very finely divided multicomponentmineral mass including liberated components which comprises conditioningsaid mass for froth flotation with (l) a reagent capable of selectivelyoiling at least one component of said mass, and (2) collectorcoatedauxiliary mineral particles characterized further by being floatable inthe presence of an aqueous pulp of said reagentized mass, and subjectingthe thus conditioned mass in the form of an aqueous pulp thereof tofroth flotation thereby to produce a froth product which is aconcentrate of oiled components of said mass in intimate associationwith said auxiliary mineral particles and a machine discharge product.

2. The method for beneficiating a very finely divided multicomponentmineral mass including liberated components which comprises forming anaqueous pulp of said mass, conditioning said aqueous pulp for frothflotation with (1) a reagent capable of selectively oiling at least onecomponent of said mass, and (2) collectoocoated auxiliary mineralparticles which are characterized by being floatable in the presence ofsaid aqueous pulp, and subjecting the thus conditioned aqueous pulp tofroth flotation thereby to produce a froth product which is aconcentrate of oiled components of said mass in intimate associationwith said auxiliary mineral particles and a machine discharge product.

3. The method of claim 2 wherein said very'finely divided mass is anaturally slimed ore.

4. The method of claim 2 wherein said finely divided mass is anartificially slimed ore.

5, The method of claim 2 wherein said very finely divided mass is anaturally slimed mineral aggregate.

6. The method of claim 2 wherein said very finely divided mass is anartificially slimed mineral aggregate.

7. The method of claim 2 wherein said very finely divided mineral massconsists essentially of 200 mesh particles.

8. The method of claim 2 wherein said auxiliary mineral particles are--325 mesh.

9. The method of claim 2 including the additional step of separating theauxiliary mineral particles from the oiled component of said mass.

10. The method for beneficiating a multicomponent mineral mass includingliberated components and being further characterized by consistingpredominantly of particles finer than 200 mesh which comprises formingan aqueous pulp of said mass, conditioning said aqueous pulp for frothflotation with l) a reagent capable of selectively oiling at least onecomponent of said mass, and (2) auxiliary mineral particles having awater-repellent coating on the surface thereof and being furthercharacterized by being fioatable in the presence of said aqueous pulp,said auxiliary mineral particles being employed in an amount by weightat least equal to that of the component of said mass which isselectively oiled, and subjecting the thus conditioned aqueous pulp tofroth flotation thereby to produce a froth product which is aconcentrate of oiled components of said mass in intimate associationwith said auxiliary mineral particles and a machine discharge product.

11. The method for beneficiating a very finely divided multicomponentmineral mass including liberated components which comprises forming anaqueous pulp of said mass in intimate association with particles of anauxiliary mineral, conditioning said aqueous pulp for froth flotationwith a collector reagent capable of selectively oiling certaincomponents of said mineral mass whereby residual components of saidmineral are water-wettable, said reagent also being capable of oilingsaid particles of auxiliary mineral, and subjecting the thus conditionedpulp to froth flotation thereby to produce a froth product which is aconcentrate of oiled components of said mineral mass in intimateassociation with particles of said auxiliary mineral and a machinedischarge product consisting of water-wettable residual components ofsaid mass.

12.. The method for improving the brightness of kaolin clay having colorbody impurities mechanically associated therewith compn'sing forminga'dispersed aqueous pulp of said clay, conditioning said aqueous pulpfor froth flotation with (l) a collector reagent capable of selectivelyoiling said color body impurities, and (2) collector-coated particles ofan auxiliary mineral, said particles being further characterized bybeing floatable in said pulp, and subjecting the thus conditionedaqueous pulp to froth flotation thereby producing a froth product whichis a concentrate of said color body impurities in intimate associationwith said auxiliary mineral particles and a machine discharge productwhich is a concentrate of clay of enhanced brightness.

13. The method for beneficiating kaolin clay discolored withmechanically associated color body impurities which comprises forming adispersed aqueous pulp of said clay, conditioning said aqueous pulp witha collector reagent capable of selectively oiling said color bodyimpurities, separately forming an aqueous pulp of particles of anauxiliary mineral, reagentizing said auxiliary mineral pulp with areagent capable of collecting said particles of auxiliary mineral whenadmixed with said aqueous clay pulp, admixing said reagentized pulps,subjecting the admixed reagentized pulps to froth flotation, therebyproducing a froth product which is a concentrate of oiled color bodyimpurities originally in said clay in intimate association withparticles of said auxiliary mineral and a machine discharge productwhich is a concentrate of clay of enhanced brightness.

14. The method for bcneficiating kaolin clay discolored withmechanically associated color body impurities which comprises forming adispersed aqueous pulp of said clay and particles of an auxiliarymineral. conditioning said aqueous pulp for froth flotation in thepresence of a collector reagent capable of selectively oiling color bodyimpurities in said clay and also capable of collecting said particles ofauxiliary mineral, and subjecting the thus conditioned aqueous pulp tofroth flotation thereby producing a froth product which is a concentrateof said color body impurities in intimate association with saidparticles of auxiliary mineral and a machine discharge product which isa concentrate of clay of enhanced brightness.

15. The method for removing a mechanically separable color body impuritycomprising a titaniferous mineral from kaolin clay which comprisesforming a dispersed aqueous pulp of said clay. conditioning said aqueouspulp for froth flotation with (l) a negative-ion collector reagentselective to the color body impurity in said kaolin clay. and (2)collector-coated particles of an auxiliary mineral capable of floatingin said aqueous pulp, and subjecting the thus conditioned aqueous pulpto froth flotation in an alkaline circuit thereby producing a frothproduct which is a concentrate of said color body impurities in intimateassociation with particles of said auxiliary mineral and a machinedischarge product which is a concentrate of bencficiated clay.

16. The method of claim 15 wherein said kaolin clay and said auxiliarymineral are concurrently reagentized.

17. The method of claim 15 wherein said kaolin clay and said auxiliarymineral are separately reagentized.

18. The method of claim 15 wherein said kaolin clay and said auxiliarymineral are concurrently reagentized in the form of an admixed aqueouspulp thereof with a higher fatty acid collector.

19. The method of claim 15 wherein said kaolin clay and said auxiliarymineral are separately reagentized, each with a higher fatty acidcollector.

20. The method of claim 15 wherein said aqueous pulp is conditioned forfroth flotation with at least one material selected from the groupconsisting of neutral hydrocarbon oils and water-insoluble oil-solublepetroleum sulfonates.

21. The method of claim 15 wherein said aqueous pulp is conditioned forfroth flotation with a least one material selected from the groupconsisting of neutral hydrocarbon oils and water-insoluble oil-solublepetroleum sulfonates and with ammonium sulfate.

22. The method for removing a mechanically associated color bodyimpurity comprising a titaniferous mineral from kaolin clay whichcomprises forming a dispersed aqueous pulp of said clay, conditioningsaid aqueous pulp for froth flotation with (l) a higher fatty acidcollector reagent selective to said color body impurity, (2) particlesof an auxiliary mineral collector coated with a higher fatty acid and(3) at least one material selected from the group consisting of neutralhydrocarbon oils and water-insoluble oil-soluble petroleum sulfonates.and subjecting the thus conditioned aqueous pulp to froth flotation inan alkaline circuit thereby producing a froth product which is aconcentrate of said color body impurities in intimate association withparticles of said auxiliary mineral and a machine discharge productwhich is a concentrate of beneficiated clay.

23. The method of claim 22 wherein said kaolin clay and said particlesof auxiliary mineral are concurrently reagentizcd in the form of anadmixed aqueous pulp thereof.

24. The method of claim 22 wherein said kaolin clay and said particlesof auxiliary mineral are separately reagentized, each in the form of anaqueous pulp, and the reagentized aqueous pulps are admixed.

25. The method of claim 22 wherein said particles of auxiliary mineralare finer than 325 mesh.

26. The method of claim 12 wherein said auxiliary mineral is calciumcarbonate and it is employed in amount of 5% to 200%, based on theweight of said clay.

27. The method of claim 12 wherein said dispersed aqueous pulp of clayis formed by dispersing clay in sodium silicate solution.

References Cited in the file of this patent UNITED STATES PATENTS2,569,680 Leek Oct. 2, 1951 UMTE sums PATENT owIcE CETEQATE F EETWNPatent N0a 2 990 958 July 4 1961 Ernest W, Greene et a1.

It is hereby certified that error appears in the above numbered pair entrequiring correction and that the said Letters Patent should read ascorrected below.

Column 1, line 69, for "with" read witheut column 4, line 63 after"choice" insert of column 7d, lines 10 and 11, for Thompson Weinman 81Company read Thompson Weinman Company line 30, 01:- "to" read two eSigned and sealed this 14th day of November 1961c (SEAL) Aimee ERNEST WSKDEB DAVID L LADD Attesting Officer Cemmiesicmer cf Patents USCUMM-DC

1. THE METHOD FOR BENEFICIATING A VERY FINELY DIVIDED MULTICOMPONENT MINERAL MASS INCLUDING LIBERATED COMPONENTS WHICH COMPRISES CONDITIONING SAID MASS FOR FROTH FLOTATION WITH (1) A REAGENT CAPABLE OF SELECTIVELY OILING AT LEAST ONE COMPONENT OF SAID MASS, AND (2) COLLECTORCOATED AUXILIARY MINERAL PARTICLES CHARACTERIZED FURTHER BY BEING FLOATABLE IN THE PRESENCE OF AN AQUEOUS PULP OF SAID REAGENTIZED MASS, AND SUBJECTING THE THUS CONDITIONED MASS IN THE FORM OF AN AQUEOUS PULP THEREOF TO FROTH FLOTATION THEREBY TO PRODUCE A FROTH PRODUCT WHICH IS A CONCENTRATE OF OILED COMPONENTS OF SAID MASS IN INTIMATE ASSOCIATION WITH SAID AUXILIARY MINERAL PARTICLES AND A MACHINE DISCHARGE PRODUCT. 